Today I Learned …

The thin, gray TelefonPlan tower in Stockholm, Sweden, looks pretty drab during the daytime. At twenty stories, it rises above the surrounding buildings — but it’s a far cry from being the world’s tallest tower. So what makes it so special? The building transforms at night, when colorful lights shine through the windows of the top ten floors. Now take another look, and you’ll see that the colors in the windows have changed. That’s because the lights can be controlled by a phone app — and anyone can change them. The installation is called “Color By Numbers”, and was only meant to run for one year. It proved so popular, though, that it has been lighting up the Telefonplan Tower since 2011. Color changes can be made by calling a phone number and using the keypad to select a floor and color. You can even watch a live feed of the building as the colors change. (From National Geographic Kids Weird But True: World 2023)